An overground mobility aid is needed to enable continuation of gait training and ambulatory activities performed in stable railed environments such as parallel bars and treadmills for those requiring balance support as well as significant upper body support. Normal gait kinematics includes in part, erect posture, reciprocating UE movement (and UEs moving out of phase, and UE movement out of phase with reciprocating LE), and associated trunk rotation. Reciprocating gait also refers to those patterns which incorporate increasing amounts of UE support for the opposite LE (two and four point gait).
The goal when walking with mobility aids is to achieve stability and the most efficient gait pattern. It is understood that weight bearing through the upper limbs is unnatural and is preferentially minimized when using mobility aids.
It is well documented that arm movement when walking is advantageous mechanically to enhance gait efficiency and stability. Trunk rotation is needed for normal LE biomechanics. Neuromechanical connections between upper and lower limbs exist, suggesting neurologic benefit of UE movement during locomotor activities. In part, rhythmical repetitive reciprocating movement during repetitive stepping training is known to enhance recovery of LE function. Arm swing in neurologic gait rehab is recommended (Meyns et al, 2013). Reciprocating UE movement enhances gait velocity, an important indicator of ambulatory ability, a standard gait rehab goal, and often a primary concern of mobility aid users. Furthermore, walking and running with elbows flexed 90 degrees is known to be more efficient. It would be desirable to have a device offering forearm support and enablement of rhythmical reciprocating UE movement.
Arm swinging with mobile grip handle support has been shown to enhance velocity and reduce UE weight bearing on treadmills in comparison to walking with static grip support (Stephenson et al, 2010). Translation of this finding, mobile grips may provide the same benefits if introduced to another form of railed device, framed walking aids. Excessive gripping pressure is associated with UE weight bearing and is understood to create aberrant heart rate and other objective data during treadmill training (Berling et al, 2006). A means to minimize gripping pressure with use of all railed devices, including wheeled mobility aids, would be desirable.
Conclusions drawn from studies examining UE weight bearing and movement during walking on a treadmill may be applicable to railed wheeled devices. Stroke survivors exhibited enhanced gait velocity when walking on a treadmill using mobile grip handles (Umker et al, 2015). Subjects with traumatic brain injury, cerebro vascular accident (CVA) or stroke, and multiple sclerosis were able to walk faster when gripping a rail instead of walking without UE support (Williams et al, 2011). A walker with mobile grip handles on the upper rails is needed.
It has been shown that walking with mobility aids which enable reciprocating UE movement is correlated with enhanced UE movement when not using or when no longer needing to use the assistive device (Tester et al, 2011). It would be desirable if a wheeled device enabled more natural UE movement irregardless of the amount of support needed.
Crutch use enables reciprocating arm movement yet requires additional coordination and provides less support than a walker. Full shoulder and hip extension range of motion (ROM) are often not achieved with use, hence biomechanics are compromised. When minimal weight bearing support is needed, yet reciprocating gait pattern is desired, such as with exoskeleton use and body weight support, crutches do not enable rhythmical repetitive UE movement. Canes enable UE movement yet may not provide adequate support.
Carter (U.S. Pat. No. 2,362,466) discusses a walker which provides for active alternating rotational movement of the upper torso. The user statically grips the side rails and axillary supports (supports under armpits/axilla or ‘crutch-like’ support assemblies) oscillate about fixed points on the side frame. Movement of one side of the upper body does not create equal and opposite motion of the second side and good bilateral UE function is needed for use. Reciprocating movement of an UE upon the frame is not created. In addition, mobile grips/grip handles or mobile forearm supports are not mobile upon the side frame(s). Schultz (U.S. Pat. No. 4,748,994) describes a device with UE support assemblies which can be repositioned along the side rails prior to use yet assemblies are statically positioned during use and statically positioned UEs manage the device.
Pak (U.S. Pat. No. 8,726,922), Murcott (U.S. Pat. No. 3,098,651) and Edwards (U.S. Pat. No. 3,442,276) discuss walkers with hinged connections between the front and side frames. The application of these devices is limited to users with good bilateral UE function. Features do not facilitate alternating UE movement. LE movement which is in phase with reciprocating UE movement as opposed to out of phase, is facilitated with these devices related to the positioning of the front frame member when one side is advanced. Wheels must be introduced in order to perform more rhythmical UE movement. This presents stability concerns particularly with increased UE weight bearing.
Rollators are three or four wheeled devices increasingly being used by an aging population wishing to remain strong and active. Users often desire to walk with a gait pattern which is as natural as possible. Grip handles or forearm supports are typically statically and symmetrically positioned on these devices, which is unnatural. Stability is lacking compared to devices with two wheels. A stable device enabling more natural gait pattern is needed.
Devices requiring good bilateral UE function and advanced via reciprocating UE movement against resistance may have limited application to the fit, healthy population. Vangsgaard (WO 2017032376) presents a device with levers which drive front or rear wheels. Features do not provide constraint for slaloming. Kochs' (DE10201511748483) device provides levers pushed by the UEs against resistance and this causes forward movement of the device. Judjahn (DE 102007015106) and JP 2009106446) also present devices with levers gripped by the user to drive the wheels. A device is needed which enables a more natural gait pattern and does not rely on good upper body function to manage. A device is needed which could variably be used to enhance upper body strengthening by addition of resistance mechanism to the mobile component.
A common concern related to use of walkers and rollators is the flexed posture associated with use. UE forces can be directed horizontally parallel to the ground and erect posture achieved when used for balance support. Weight bearing through UEs necessitates anterior displacement of the center of gravity because the UEs simultaneously advance the device and this is accomplished by forward leaning or flexing the spine and/or hips. Forearm supports can be used to facilitate more erect posture and reduced UE weight bearing yet if used for more than light support, upper body forces are necessarily directed angled downward. A paradigm shift in how mobility aids are managed is needed. A walker and rollator is needed which is advanced via bodily contact instead of being managed by the UEs.
When light/balance support is needed, it would be desirable to have a wheeled mobility aid or rehab or therapeutic device which is advanced preferentially by bodily contact which could be used with statically positioned UEs as well as with mobile UEs.
Continuous stepping with a wheeled device involves more hip extensor activity yet hip extension range of motion is typically reduced and kinetics are altered. When discontinuous stepping patterns are performed, even when walking with light upper body support, the UEs may be used to provide bracing to facilitate hip flexion to advance a LE instead of activating hip extensors to a greater extent. Bateni et al. (2005) discuss the potential for variability in horizontally directed (propulsive or braking) forces with use of walkers. It would be desirable to have features which facilitate enhanced lower body propulsion to advance the device.
Static UE positioning does not enable performance of compensatory gait patterns which may be performed in parallel bars. This is unsafe and inefficient. A device is needed which enables gait patterns achievable in parallel bars for safety and efficiency. It would be desirable to have a wheeled walker with braking capability which enabled alternating UE movement and more vertically directed upper body forces for provision of support.
Suica et al (2016) and Maguire (2017) note that excessive compensatory use of UEs is common with rollator use and this may negatively impact LE strength over time. Alkjaer et al (2006) also found significant alterations in LE muscular function with rollator use. Rollator use is particularly desirable to those wishing to remain independent. LE strength is integral to functional independence. A rollator solution is needed which provides for more normalized LE function.
Walking ability with wheeled devices necessarily in part reflects upper body function. Also, adequate upper body function is needed to use wheeled devices. Minimization of UE management would be desirable in order to be able to more accurately assess lower body functional status. Such a device could be used as a screening tool for fall risk associated with use of a particular type of wheeled device.
Schulein et al (2017) discuss the importance of delineating the impact of walker use on gait parameters known to directly impact falls in the elderly population. Excessive UE management of these devices significantly impacts measures reviewed in these papers. UE management of mobility aids places additional cognitive demands and may be particularly detrimental in the presence of cognitive impairment.
For a given amount of physical work, energy expenditure is greater when the same amount of work is performed by UEs as compared to the LEs. It is well known that energy expenditure related to UE management of mobility aids is considerable. It would be desirable if a wheeled device could be advanced via bodily contact instead of by UE management.
Increased use of forearm supports on wheeled devices is needed as well as a device which enables improved ambulation with use of this type of UE support surface. Assemblies predominantly are available for attachment to standard devices, thereby introduced without hand brakes. Stability is often a concern related to need to be used on a wheeled device, and typically one with swivel wheels to enable steering. Support surfaces typically are not ergonomically designed to accommodate UE dysfunction. A mobility aid with various types of readily interchangeable grip and forearm support assemblies with hand brakes is needed. Other walkers and rollators which enable reciprocating UE incorporate gripping support. A device which enables all of the reciprocating gait patterns whilst one or both forearms is supported is needed. Training in proper biomechanics in all orthopedic gait rehabilitation including following total hip and total knee replacement is significantly compromised when using standard walkers and rollators. It would be desirable to have a gait training device which encouraged normal hip and knee function.
Prior art focused on devices for use in gait training includes devices propagated by work performed by the upper body [Lutz (U.S. Pat. No. 8,251,079). Albani et al (EP0624357) Katamoto (JP 2013116146)]. A device which normalizes upper and lower body movement whilst minimizing UE work is needed.
Pinero (U.S. Pat. No. 7,422,550) presents a training device which addresses the need for facilitation of reciprocating LE movement. A device which mechanically mobilizes the UEs in reciprocating manner is needed.
Exaggerated upper limb movement to improve locomotor ability following neurotrauma is discussed in the art (Zehr et al, 2016). Current solutions for creating exaggerated and/or repetitive reciprocating UE during repetitive stepping training over ground and on the treadmill includes holding and moving poles parallel to the ground. This requires adequate UE function and physical assistance. A mechanical means is needed to enable UE movement during long duration stepping activities is needed. This feature would enhance UE movement symmetry. It is well known that fall risk in the elderly is correlated with gait asymmetries. It would be desirable to have a device which could be used for daily training to enhance gait symmetry.
Specifically related to Parkinson's Disease (PD), incorporation of reciprocating UE movement and associated trunk rotation in rehab is advised. The UEs are statically positioned on current devices designed for the PD population. Decreased arm swing is one of first physical signs of the disease. A device which could be used throughout the course of this progressive disease would enable freely reciprocating UE movement as well as a means to potentiate this movement in later stages. The same device could be used in sitting and standing. It would be desirable to have locking wheels for stationary activities.
Warlop et al (2017) recommend incorporation of rhythmic external audible cuing to bypass the basal ganglia in PD. Audible cuing is also advised for spinal cord injury (SCI) gait rehab. Reciprocating UE movement would provide a functionally relevant means to accomplish this.
Stroke (CVA) gait rehab is the largest cause of gait dysfunction in the U.S. A device is needed which enables a stronger UE to mobilize a weaker UE in reciprocating fashion. A mechanical means to incorporate the upper body into gait rehab is needed. An adequately supportive device which facilitates work on upper and lower body symmetry is needed. Such a device could also be used for bilateral UE training in sitting.
Typically in the case of unilateral UE dysfunction, the involved UE is statically supported or unsupported and not mobilized when using a cane or hemiwalker. A mobility aid which does not require good upper body function, as well as enablement of walking similar to that performed in parallel bars would be desirable for CVA gait rehab (Allet et al, 2009). Klarner et al (2016) discuss the unmet need to incorporate UE movement in CVA gait rehab.
Suica et al (2016) write that current walkers and rollators which enable excessive stability provision by the UEs thereby diminishing physical challenge to the LEs may not be optimal devices to use for stroke (CVA) rehab. It would be desirable to have a training device and mobility aid which enabled UE movement and adjustability of this movement in order to alter stability.
Recent findings related to plasticity of the nervous system have expanded endeavors to improve gait function in those with neurologic disorders. Training involving repetitive stepping training is called locomotor training. Behrman et al (2000) list principles known to enhance locomotor training. This list includes: “(1) generating stepping speeds approximating normal walking speeds (0.75-1.25 m/s) (2) providing the maximum sustainable load on the stance limb (3) maintaining an upright and extended trunk and head (4) approximating normal hip, knee, and ankle kinematics for walking (5) synchronizing timing of extension of the hip in stance and unloading of limb with simultaneous loading of the contralateral limb (6) avoiding weight bearing on the arms and facilitating reciprocal arm swing (7) facilitating symmetrical interlimb coordination, and (8) minimizing sensory stimulation that would conflict with sensory information associated with locomotion.” Problems associated with walkers as related to adhering to these principles are addressed by Behrman et al (2005), which describe challenges adhering to these principles with currently available mobility aids.
Maguire et al (2017) present problems related to rollator use related to neurologic gait rehab. LE muscular activity, hip loading, and hip extension range of motion are reduced, excessive use of the UEs is predominant, and collision of rear wheels with feet serve as confusing cutaneous inputs. A device advanced by the body instead of by the UEs is advised.
Even in the presence of normal upper body function, performing repetitive stepping activities on treadmills and when standing, or walking over ground with body weight support, patients may tend to statically position UEs. It would be desirable to have a device which enabled, facilitated, and potentiated reciprocating UE movement for repetitive stepping activities over ground or when on the treadmill. It would be desirable to have a device which could also be used to perform reciprocating gait patterns involving heavier UE support, such as with forearm supports. Such a device could be used for training to minimize UE weight bearing when light support is needed and would enable the same biomechanics when heavier support is needed in the absence of deweighting devices.
Fulk et al. (U.S. Pat. No. 8,573,612) present a device to address the above principles. The device is managed by the UEs, with statically positioned grips on the frame; neither reciprocating movement of one UE or symmetrical out of phase UE movement can be facilitated; device is lacking in stability for safe use when more than light support is needed.
A device is needed which enables enhanced adherance to a greater number of principles known to enhance neurorecovery.
A need exists for an improved arrangement which provides solutions for the above problems as well as others.